An ion generator includes a blower, a housing having two flow passages for allowing the passage of air sent out from the blower in the same direction individually and discharging the air to outside, and ion generation units attached to a channel wall of each of the flow passages respectively and generating ions. The ion generator discharges the ions (positive ions and negative ions) generated by the ion generation units and the air flowing through the flow passages to an indoor space so that bacteria floating in air is eliminated and virus is inactivated (for example, Japanese Patent Application Laid-Open No. 2010-80425). The ion generation unit has a needle-shaped discharge electrode and a voltage application part which applies a voltage to the discharge electrode, and ions are generated by corona discharge from the discharge electrode.
Japanese Patent Application Laid-Open No. 2011-33293 describes that an electrostatic atomization apparatus (ion generator) is configured such that a discharge electrode is coupled to one surface of a Peltier element where the one surface absorbs heat due to an applied voltage and the other surface emits heat; a heat sink with a radiation fin is coupled to the other surface of the Peltier element; the discharge electrode is cooled by a voltage applied to the Peltier element; the moisture in air is condensed on the tip of the discharge electrode; an electrostatic atomizing phenomenon occurs on the tip of the discharge electrode by a voltage applied to the discharge electrode; and then electrostatic atomized water particles with negative polarity are generated.